package top.hzy520.personalblog.util;


import org.commonmark.Extension;
import org.commonmark.ext.gfm.tables.TableBlock;
import org.commonmark.ext.gfm.tables.TablesExtension;
import org.commonmark.ext.heading.anchor.HeadingAnchorExtension;
import org.commonmark.node.Link;
import org.commonmark.node.Node;
import org.commonmark.parser.Parser;
import org.commonmark.renderer.html.AttributeProvider;
import org.commonmark.renderer.html.AttributeProviderContext;
import org.commonmark.renderer.html.AttributeProviderFactory;
import org.commonmark.renderer.html.HtmlRenderer;

import java.util.*;

public class MarkdownUtils {
    /***
     * markdown格式转换为HTML格式
     * @param markdown
     * @return
     */
    public static  String markdownToHtml(String markdown){
        Parser parser=Parser.builder().build();
        Node document=parser.parse(markdown);
        HtmlRenderer renderer=HtmlRenderer.builder().build();
    return renderer.render(document);
    }

    /****
     *  增加扩展(标题错点，表格生成)
     *  Markdown转换成HTML
     * @param markdown
     * @return
     */
    public static String markdownToHtmlExtensions(String markdown){
     //h标题生成id
        Set<Extension> headingAnchorExtensions= Collections.singleton(HeadingAnchorExtension.create());
        //转换table的html
        List<Extension> tableExtensions= Arrays.asList(TablesExtension.create());
        Parser parser=Parser.builder()
                .extensions(tableExtensions)
                .build();
        Node document=parser.parse(markdown);
        HtmlRenderer renderer=HtmlRenderer.builder()
                .extensions(headingAnchorExtensions)
                .extensions(tableExtensions)
                .attributeProviderFactory(new AttributeProviderFactory() {
                    public AttributeProvider create(AttributeProviderContext Context) {
                        return new CustomAttributeProvider() ;
                    }
                })
                .build();
        return renderer.render(document);
    }

    /****
     * 处理标签
     */
    static   class CustomAttributeProvider implements AttributeProvider{

        @Override
        public void setAttributes(Node node, String tagName, Map<String, String> attributes) {
          //改变a标签的target属性为_blank
            if (node instanceof Link){
            attributes.put("target","_blank");
            }
            if (node instanceof TableBlock){
                attributes.put("class","ui celled table");
            }
        }
    }
}
